21621701 has 8 divisors (see below), whose sum is σ = 22037184. Its totient is φ = 21209440.

The previous prime is 21621697. The next prime is 21621709. The reversal of 21621701 is 10712612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21621701 - 2² = 21621697 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621709) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15890 + ... + 17196.

It is an arithmetic number, because the mean of its divisors is an integer number (2754648).

Almost surely, 2^21621701 is an apocalyptic number.

It is an amenable number.

21621701 is a deficient number, since it is larger than the sum of its proper divisors (415483).

21621701 is a wasteful number, since it uses less digits than its factorization.

21621701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1611.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 21621701 is about 4649.9140852278. The cubic root of 21621701 is about 278.5885646514.

It can be divided in two parts, 21621 and 701, that added together give a palindrome (22322).

The spelling of 21621701 in words is "twenty-one million, six hundred twenty-one thousand, seven hundred one".